Optical fiber splicing machines are important apparatus and tools used in the process of manufacturing of equipment that are frequently found in fiber communication, fiber sensing, and fiber lasers, to name a few. Currently, there are two types of splicing machines available in the market: a first one that is relatively low cost but only suitable for splicing regular fibers, and a second one that is adapted for splicing linear polarization maintaining (PM) fibers in additional to regular fibers. Here and throughout this application, the term “regular fiber” refers to any fiber whose axis cross-section has circular symmetry with no particular axis orientation difference.
Splicing machines that are suitable only for regular fibers have thus far found their relatively high market demand and are widely used. Thanks to its low technical entry level, there are more than a dozen companies presently being able to manufacture and offer this type of splicing machines. On the other hand, there is a very limited and small number of companies in the world that are currently capable of manufacturing splicing machines suitable for handling linear PM fibers. Not only there is high equipment cost associated with the purchasing of these types of “special” splicing machines, which may be priced at tens to hundreds of thousand dollars, it is also known to be very costly to perform daily maintenance of these types of splicing machines that are made for handling linear PM fibers.
The low availability and high cost associated with splicing machine capable of handling linear PM fibers may be attributed, at least partially, to its high technical entry level due to, for example, difficulty in optical side-imaging processing and developing and lack of understanding of algorithm of mathematical computation in supporting the imaging processing. Moreover, the design concept of current splicing machines (for handling liner PM fibers) relies on integrating all of the required components and parts associated with the splicing process into an extremely compact mechanical structure in a precise manner, which makes it all too difficult to achieve a good compromise among cost, precision, and ease of handling. Moreover, the relatively low market demand, compared with those that are suitable only for regular fibers, also contributed to the slow progress of development of an affordable and yet reliable splicing machine that may splice PM fibers with high performance.
Nevertheless, even those splicing machines that are available in the market still have their unique limitations. For example, most of these splicing machines can only handle regular PM fibers which are mainly linear PM fibers, but will not be able to handle, or will fail to handle, tens of other types of specialty fibers currently available and being used in the fiber industry. Using the available splicing machine to handle specialty fibers or, for example, to splice different types of fibers together may often lead to misalignment between axes of the spliced fibers, which consequently results in high insertion loss at the splicing point and breakage thereof in a worst scenario, creating high re-work rate and slowing down of manufacture production cycle. This is because with specialty fibers such as, for example, elliptical PM fibers whose cross-sectional structure varies along the length of fiber, different from that of a linear PM fiber, the algorithm commonly used in the computation and imaging processing of currently available splicing machines simply does not apply and may therefore produce false results.